Atanasoff’s Computer

Background In 1932 Vannevar Bush of the Massachusetts Institute of Technology completed a mechanical computer called the differential analyzer which did caculus by rotating gears and shafts Electronic computers operate primarily by means of such electron devices as vacuum tubes, transistors or, now microchips; electrons, rather than computers parts do most of the moving The first electronic computer was generally agreed to be the Colossus, build by Alan Turing and M.H. Newman at the Bletchey Research Establishment in England The late recognition of Atanasoff’s computer was discovered due to a lawsuite initiated in1967 between Sperry Rand Corp and Honneywell Inc. Sperry had bought the patent to the ENIAC and was charging royalties. Honeywell v. Sperry Rand Judge Earl R Larson, sated “ Mauchly and Eckert did not themselves first invent the automatic electronic digital computer, but instead derived that subject from Dr Jhon Vincent Atanasoff” (This made Atanasoff’s creation be classified as the earliest know electronic comp)

Background Cont’t Winter of 1937 Atanasoff had decided on a few principles for the computer: –The storage of data should be separated from the computational function –the method of computation should be digital rather than analog –The machine would express numbers as digits rath than by analogy to some physical quantity (such as the distance along the axis of a slide rule) –Calculations in terms of bases other than base 10 He resolved to rely on electronic switches (electric decses that direct the flow of electical signals) rather than mechanics to carry out the comps control and arithmetic functions Binary numbers would act on those numbers by following rules of logic instead of direct counting A positive charge on one end of a capacitor could represent the number 1, and no charge could stand for 0

Prototype

“Abacus”

Driving Force Iowa State College1930s JVA on Physics faculty; looking for ways to simplify his calculating burden –did a study of existing computing equipment in 1935 and 1936; experimented with using 30 Monroe calculators on a common shaft; knew of the Bush Differential Analyzer at MIT modified leased IBM punched card equipment, much to the consternation of IBM salesman

Solve for N He wanted to solve n equations with n unknowns (specifically 29) 29 x 28 x 27 x 26 x25 x 24 x 23 x 22 x 21 x 20 x 19 x 18 x 17 x 16 x 15 x 14 x 13 x 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 ( n * n-1) / 2 or (29 * 28)/2 = 406 iterations

Problems/Solutions Initially working on the project his thoughts did not “Jell” and he became distressed because of this. –Took a drive (at high speeds) focusing on driving. After 200 or so miles stopped at a road house to get a drink. –Atanasoff appreciated that the mind needs variety and relaxation in order to perform creatively. Having conceived of some fundamental principles, he then allowed “a kind of cognition” to come into play. –Such a reliance on intuition may not be in accord with the common perception of scientific investigation as a strictly rational activity Capacitors have a tendency to lose their charge. –Regenerating the memory, a process called “jogging” would restore the charge in a capacitor so that if the capacitor was in say the plus state, 1, it would remain that way. This would stop the change/decay to 0 over time. The punch-card input-output systems generated an error about once ever punching and reading operations in the ABC Only raised $6,000 to fund and work on this system –Compared to ½ million for the ENIAC, which was given military funding

Contributions Comparing the ABC with Bush’s differential analyzer –ABC attained an accuracy that was 1000 times greater than was possible with the differential analyzer –The precession could easily increased more if needed by adding more digits. Compared to analog where it is difficult and expensive. Store his binary digits in capacitors due to cost and could send signals to the computational unit with out their having to be amplified –He considered vacuum tubes and ferromagnetic materials Developed a logic circuit (Black Box) –Build out of vacuum tubes and would receive signals from the capacitors in the memories. The capacitors were called keyboard abacus and counter abacus –Logic circuits today are stored in chips that are much faster than vacuum tubes but perform basically the same functions

Contributions Con’t He could have claimed to have come up with the concepts of: –Electronic digital computation –Electronic switching in computers –Circuits for logical addition and subtraction –Separation of processing from memory –Capacitor-drum memories –Memory regeneration –Use of the binary number system in electronic computing –Modular units –Vector processing –Clocked control of electronic operations

ABC Parallel Machine? His system had one logic circuit, consisting of seven tubes, added or subtracted the coefficient, in the keyboard to or from the coefficient in the counter, leaving the sum or difference in the counter At the same time the other circuits processed the other pairs of coefficients in the same way. (this process which a number of operations are performed in parallel, is called vector operations, and computer carrying out such operations is a vector processor –A vector processor, or array processor, is a CPU design that is able to run mathematical operations on multiple data elements simultaneously –Parallel computing is a form of computing in which many instructions are carried out simultaneously. Parallel computing operates on the principle that large problems can almost always be divided into smaller ones

1. Separate memory and computation 2. Digital (rather than analog) 3. Electronic switches 4. Binary number system 5. Calculate by logic nor counting 6. Memory required “jogging” 7. Capacitor for memory (ICs today) 8. Modular units 9. Vector processing 10. Control by a clock Architecture of ABC

ABC vs ENIAC ENIAC was the first general purpose electronic computer ENIAC could be programmed for different problems by altering the configuration of wires plugged into a control panel ENIAC calculated by direct counting and it did so in base 10 ENIAC had thousands of vacuum tubes and it memory was electronic ABC Was designed to be a special purpose machine ABC calculated by logic and it did so in base 2 ABC had hundred of vacuum tubes and its memory was on rotating drums Both used electronic switching to control the operations of the computer Both had the idea that digital electronic machines could do calculus with greater precision and speed than Bush’s differential analyzer

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